Mechanical optical scanner

ABSTRACT

A magnifying and reading device for microfiche films. The required magnification is achieved by breaking up the object into a series of narrow segments and sequentially projecting them onto a viewing screen by a rocking mirror.

Yeviek 1 May 22, 1973 [54] MEQHANECAL @PTICAL SCANNER [56] ReferencesCited [75] Inventor: George J. Yevick, Leonia, NJ. UNITED STATES PA TS[73] Assignee: Personal Communications, inc, 3,658,415 4/1972 Miles.....353/78 Stamford Comm 3,637,281 1 1972 Gull ....178/7.6 3,319,5175/l967 Rondas et al ..353/27 [22] Filed: July 21, 1971 PrimaryExamineF-Louis R. Prince 7 [211 N0 44 Assistant Examiner-Steven L.Stephan Attorney--larold T. Stowell et a1. [52] U.S. Cl. ..353/30,353/98, 353/l2l,

353/122, 355/45, 355/84 [57] ABSTRACT [5 U 5 CLmGGgb 21/26 60% 21/28 60%21/00 A magnifying and reading device for microfiche films. [58] wieldof Search ..353/30, 98,121, Th d d b b 353/122; 178/16; 355/8 47 51 6465, 50 h e require magni ica ion isfac ieve y rea mg up 44, 45; 356/24 te ob ect into a series 0 narrow segments and sequentially projectingthem onto a viewing screen by a rocking mirror.

6 (Ilaims, 8 Drawing Figures MECHANICAL OPTICAL SCANNER This inventionrelates to a device for magnifying printing or other information whichhas been greatly reduced and stored on transparent films, commonlytermed microfiche films. The invention exhibits utility in thepresentation of magnified and stored information from any type of film,

The prior art is aware of devices of this general type, often known asmicrofilm readers. Such devices generally operate under and employ thesame basic optical arrangement that is used in motion pictureprojectors, slide projectors, etc. The film carrying the reducedinformation is illuminated and the rays passing through it traverse anoptical system defined by one or more magnifying lenses. The lensescause the light rays which have passed through the film to diverge andsubsequently impinge upon a viewing screen. In order to achieve therequired magnification, such systems require a large light cone, i.e., acone whose apex or point is the film and whose base is the viewingscreen. This cone is rather long, as in the case of a motion pictureprojection system or a conventional microfiche reader. The length of thecone may, however, be diminished by increasing the angle of the cone,i.e., the angle of divergence of the apex. An example of this is aconventional television tube wherein the length of the cone is rathersmall but the cone angle is rather large. Thus, prior art projectionsystems for obtaining the requisite magnifications have employed eitherlong optical cones or shorter optical cones having wide angles.

According to the practice of the present invention, both the length ofthe cone and, even more significantly, the angle of the cone, arereduced. This is effected by utilizing only a thin slice of the lightcone at any one instant of time. Thin slices of the cone are made insuccessive instants of time and each is pro jected onto a viewingscreen. Each successive instant of time produces new information on theviewing screen, carried by a new and different thin slice of the cone.The terminal ends (bases) of each of the successive thin slices of thecone impinge upon a viewing screen in a rapid manner to avoid flicker.This effective division of the optical cone into thin slices greatlyreduces the required angular size of the projection, at any giveninstant of time, onto the screen. Further, the length of the light coneis significantly reduced by the use of a plurality of mirrors whichserve to fold or compress the light slices from the cone.

IN THE DRAWINGS FIG. 1 is a schematic view of an optical projection andmagnification system according to the present invention;

FIG. 2 is a schematic view illustrating how the light cone is broken upinto a series of thin slices for projection onto a viewing screen;

FIG. 3 is a view illustrating the mode of operation of one type ofscanning device for breaking up the object into a plurality of thinwedge optical slices;

FIG. 4 is a view of an embodiment of the device of FIG. 3;

FIG. 5 is a view showing still another embodiment of the device of FIG.3;

FIG. 6 is a view of an embodiment of the device of FIG. 3;

FIG. 7 is a view of a mechanism to yield the desired synchronism betweenthe projecting rocking mirror and the object scanning means.

FIG. 8 is a view of an embodiment of the device of FIG. 7.

Referring now to the drawings, the numeral 10 at FIG. 1 represents alight source of any convenient type. The numeral 12 represents amicrofiche or other transparent film carrying information on a greatlyreduced scale. The information may be in the form of code, printing,photograph, or the like. The numeral 14 denotes a device for breaking upthe light passing through the microfiche 12 into a succession of thinoptical slices. The numeral 16 denotes a projection lens of conventionalconstruction. In such a lens, parallel light rays passing to it from thescanning device 14 diverge to thereby form a light cone. The numerals 11and 15 denote opaque screens with a slit in each, for the purpose ofgenerating a line source of light on the film 12 and for eliminatingstray light. It will be understood that lens 16 designates any desiredprojection system, such as a plurality of lenses for the purpose ofreducing chromatic abberation, etc. The numeral 18 denotes a firstreflecting surface, preferably in the form of a narrow mirror. Thenumeral 20 denotes a second reflecting surface, similar to element 18and again in the form of a narrow mirror. The numeral 22 denotes stillanother reflecting surface in the form of a mirror. The mirror 22 isrocked about an axis of rotation 24 on a bell crank lever by means of alinkage system 26 coupled to a rotating disc 28. It will be understoodthat the numeral 26 denotes any mechanism or means for rocking themirror 22. The numeral 30 denotes a conventional viewing screen and thenumeral 32 denotes a section of the viewing screen which is illuminatedby light reflected mirror 22 in the latters illustrated position. Theelements thus far described are housed and mounted in a suitable casing.In practice, the viewing screen 39 may be ofasize such as 8 a X l 1inches. FIG. 2 of the drawings will assist in understanding theoperation of the elements shown at FIG. 1. FIG. 3 of the drawingsdiscloses one method of optically dissecting or breaking up the object,here the information stored on microfiche 12. Referring to the topportion of FIG. 3, the elements of means 14 are defined by a pair ofrocking mir rors S0 and 52 which rock or oscillate in synchronism sothat the light slice 54 reflected from the first mirror 50 traverses oneof the two dimensions (either the length or the width) of the microfiche12. Referring now to the middle sketch of FIG. 3, the mirrors 50 and 52have so rotated that the light slice 54 now passes through the middle ofthe microfiche 12. Referring now to the bottom of FIG. 3, the mirrors 50and 52 have rotated such that the light slice 54 now traverses the leftmost portion of the microfiche 12. After the indicated traversal fromright to left, the light slice 54 now traverses from left to right andthe cycle is completed. The

geometric perpendicular or normal to each of the mirrors 50 and 52 isindicated by a short arrow.

The reader now will be in a position to comprehend the basic mode ofoperation of the system. Referring again to FIGS. 1, 2 and 3, theillumination source 10 is energized and light from it passes through themicrofiche 12. In the absence of the scanning device 14 slits in 11, 15,mirrors 18 and 20, the light cone from lens 16, representing theprojection through-it of the microfiche 12, would be as indicated by theletter C in FIG.

3 2 of the drawings. This may be imagined or thought of as theconventional method of magnifying and project ing information stored ontransparent films. Successive and adjacent segments of the microficheEli: are, by the practice of this invention, broken up into thin opticalwedge slices by the mechanism indicated at 3. This is shown at P16. 2 ofthe drawings wherein the letter W indicates such a edge. Light passingfrom the lens 16 falls upon the first reflecting surface The light frommirror 18 now strikes mirror thence mirror 22, and thence projected ontoscreen The intersection of the wedge W on the screen 36 is indicated bythe numeral 32.

In the next instant of time, the scanning mechanism 14 illustrated atMG. 3 now directs the reflected beam 54 to an adjacent portion ofmicrofiche 12. The light entering lens 16 now defines (from thisadjacent portion) a new and different thin wedge optical slice W Asbefore, the light passes to first mirror 123, back to mirror 20, thenceto mirror 22. h/lirror 22 is operated in synchronisrn with the objectdissecting mechanism 14. The mirror 22 has now rotated somewhat andrefleets the new wed e W Referrin to H6. 2, the terminal portion of thisnew wedge W is illustrated as is indicated by the numeral This is alsoshown at FIG. 1 wherein the area encompassed by the vinculum 320 isillustrated as adjacent the terminus of 32.

The reader will now comprehend that the process of continuously scanningthe microfiche 12 by breaking it up into segments, all accomplished bythe mechanism 14, is carried out in synchronism with the rocking oroscillating mirror 22. The angular extent of the oscillation of mirror22 need only be such that the reflected light encompasses the top to thebottom of the screen 30.

Again referring to FIG. 2 of the drawings, it will be apparent that theangular extent of the conventional optical cone has been significantlydiminished. As known to those versed in the optical arts, a projectionlens such as 16 which accommodates only small angu-- lar departures fromits optical axis may be easily and more cheaply made than one which isrequired to accommodate large angular departures. Thus, reduction inexpense of an optical component is also realized by the practice of thisinvention. The mirrors 18, 21) and 22 of FIG. 2 are illustrated asspaced along the optical wedge W for convenience in illustration. Inpractice, the wedge W is folded into roughly 2% layers, as indicated atFIG. I, in order to effect reduction in length of the device. Clearly,any desired number of mirrors such as 13 and 20 may be employed in orderto effect still further reduction in size. In practice, the mirrors 18and 20, as well as mirror 22, are flat.

In order to prevent flicker on the viewing screen 30, the mirror 22 mustoscillate, in cooperation with the object dissecting mechanism 14, so asto present at least 45 or 50 intersections 32, 320, etc., each second.Stated somewhat differently, during each second, the mechanism mustdissect the object 12 at least 45 or 50 times each second. Thisfrequency stems from the persistence time of the human eye. In order toavoid distortion caused by different viewing screen areas swept out bythe various optical wedges W, the information may be recorded on themicrofiche elements 12 by placing the required information, in normalsize, on a screen such as and photographically recording it on amicrofiche by the inverse of the method just described.

Referring now to P16. 4 of the drawings, a modifica-a tion of themechanism 14 for dissecting the object is illustrated. Here, a regularpolygonal rotating mirror is positioned r=.lative to the microfiche 12and source it) in the indicated manner. The indicated rotation of themirror til] causes back and forth scanning of the microfiche T2. Theseveral planar reflecting surfaces of 6% cooperate with the slit 1? toproduce successive wedges for projection.

Referring now to FIG. 5 of the drawings, another scanning or dissectingarrangement for the mechanism 2 5 is illustrated. Here, a pair ofoptical elements 70 and 72, formed for example of glass, and square incrosssection, are rotated as indicated by the curved arrows. The ray '74passing from the lower element traverses the object 12 from right toleft and then from left to right. Light from the source Ml falling uponthe bottom face of the element '70 will be refracted as indicated due tothe greater index of refraction of the glass. After passing through theglass 70, the slice 74 is again bent, by square 72, back to the originalaxis. If desired, the refracting elements "70 and 72 may be rocked,instead of rotated.

Referring now to FIG. 6 of the drawings, still another mechanism forscanning the microfiche is illustrated. Light from lamp 10 is focused onstationary slit 11 which'is now incident on a beam splitter 65. The beamsplitter may assume the form of a partially silvered mirror. Thetransmitted light from beam splitter is incident on a rotating mirrorprism 60. Light is reflected from 60 onto rotating mirror prism 62. Theindicated mirror of 62 is parallel to the indicated mirror of 60. Lightfrom 62 is now incident on fiche 12 and passes through the film andfalls on fixed support mirror 66, is reflected back to 65 and thencethrough fixed exit slit 15 and lens 16.

In each of the embodiments of FIGS. 3 through 6, the rotation of theobject dissecting elements is synchronized with the rotation ofprojecting rocking mirror 22. This permits a homologous relation orcorrespondence between the position of the scanning ray which passesthrough the microfiche and the light cone slice projected on the viewingscreen.

FIG. 7 illustrates one mechanism for accomplishing this, and isdescribed with relation to the scanning device shown at FIG. 5.

Two gears 30 and 31 form a rocker that rocks prisms and 72 back andforth as previously described. By a linkage 26 mirror 22 is compelled torock in synchronism with prisms 70 and 72 about axis 24. Proper registryis maintained by initial angular adjustment of mirror 22.

The mirror 22. has been illustrated as rocking or oscillating about axis24. It will be apparent that the reflecting surface 22 may be rotated,instead of oscillated. If surface 22 is rotated, then the scanningmechanism must rotate. Similarly, if surface 22 is rocked or oscillated,then the scanning mechanism must likewise rock or oscillate insynchronism. In either case, the reflecting surface 22 is moving, andthis term shall accordingly encompass both the rotating and theoscillating cases.

FIG. 8 represents an embodiment of the device of FIG. 7, whereinrotation of elements 70 and 72 is carried out, together with rotation ofsurface 22, here illustrated as having four reflecting surfaces 22.Frisms 7t and 72 are caused to rotate by spring or electric motor inopposite senses of rotation. Pulleys 42 and 5-3 are connected by a beltor chain to rotate a four-sided mirror 22'. If the revolutions persecond of mirror 22 are the same as 79 and 72, they are in synchronism.Now, by initial setting of 22', the proper register of object 12 onscreen will be realized.

While mirrors have been illustrated, along with prisms, for bending ordeflecting light, other means could be used. For example, electro-opticbeam deflectors are presently known. Lead niobate crystals are capableof deflecting light, with no moving parts.

What is claimed is:

1. An optical magnifying system for projecting an image of an objectonto a screen including:

A. A source of illumination for illuminating said object,

B. A projecting lens,

C. Scanning mean for sequentially transmitting light from adjacentscanned segments of said object to said projecting lens, the projectinglens in turn forming an image of each of the scanned segments,

D. Movable reflector means positioned to intercept and reflect theimaging light to the screen so that the image of each of the scannedsegments is projected onto the screen, the reflector means being movableto reflect the projected images of each of the scanned segments todifferent areas of the screen,

E. Means for coupling the scanning means and the movable reflector meanssuch that adjacent segments of the object will be projected to adjacentareas on the screen so that the system projects an image of the entirescanned object onto the screen as the object is scanned.

2. The system of claim 1 including,

a. a plurality of mirrors positioned in the optical path between saidlens and said movable reflector means and intercepting the light fromthe illumination source,

b. said mirrors reflecting the light from said lens in a back and forth,serpentine, accordion, manner.

3. The system of claim 2 wherein the optical axis of said lens isgenerally parallel to the plane of said viewing screen, and wherein thereflecting surfaces of said plurality of mirrors are substantiallyperpendicular to said viewing screen.-

4. The system of claim 1 wherein said (c) means is defined by a pair ofplane, oscillating reflecting elements spaced from each other andbetween which a film is adapted to be placed, one of said pair receivinglight directly from said source of illumination, and the other of saidpair transmitting light to said projection lens.

5. The system of claim 1 wherein said (0) means is defined by a pair ofrotatable, polygonal, flat sided reflecting elements spaced from eachother, a fixed support mirror, and a partially-transmitting,partiallyreflecting mirror first receiving light from said source, thetransmitted light from said source then striking, in sequence, said pairof rotatable reflecting elements, thence said fixed support mirror, andback for reflection to said projecting lens from saidpartially-reflectin g mirror.

6. The system of claim 1 wherein said (c) means is defined by a pair ofoscillating or rotatable, square in cross-section, refracting elementsspaced from each other and between which a film is adapted to be placed,one of said pair receiving light directly from said source ofillumination, and the other of said pair transmitting light to saidlens.

1. An optical magnifying system for projecting an image of an objectonto a screen including: A. A source of illumination for illuminatingsaid object, B. A projecting lens, C. Scanning mean for sequentiallytransmitting light from adjacent scanned segments of said object to saidprojecting lens, the projecting lens in turn forming an image of each ofthe scanned segments, D. Movable reflector means positioned to interceptand reflect the imaging light to the screen so that the image of each ofthe scanned segments is projected onto the screen, the reflector meansbeing movable to reflect the projected images of each of the scannedsegments to different areas of the sCreen, E. Means for coupling thescanning means and the movable reflector means such that adjacentsegments of the object will be projected to adjacent areas on the screenso that the system projects an image of the entire scanned object ontothe screen as the object is scanned.
 2. The system of claim 1 including,a. a plurality of mirrors positioned in the optical path between saidlens and said movable reflector means and intercepting the light fromthe illumination source, b. said mirrors reflecting the light from saidlens in a back and forth, serpentine, accordion, manner.
 3. The systemof claim 2 wherein the optical axis of said lens is generally parallelto the plane of said viewing screen, and wherein the reflecting surfacesof said plurality of mirrors are substantially perpendicular to saidviewing screen.
 4. The system of claim 1 wherein said (c) means isdefined by a pair of plane, oscillating reflecting elements spaced fromeach other and between which a film is adapted to be placed, one of saidpair receiving light directly from said source of illumination, and theother of said pair transmitting light to said projection lens.
 5. Thesystem of claim 1 wherein said (c) means is defined by a pair ofrotatable, polygonal, flat sided reflecting elements spaced from eachother, a fixed support mirror, and a partially-transmitting,partially-reflecting mirror first receiving light from said source, thetransmitted light from said source then striking, in sequence, said pairof rotatable reflecting elements, thence said fixed support mirror, andback for reflection to said projecting lens from saidpartially-reflecting mirror.
 6. The system of claim 1 wherein said (c)means is defined by a pair of oscillating or rotatable, square incross-section, refracting elements spaced from each other and betweenwhich a film is adapted to be placed, one of said pair receiving lightdirectly from said source of illumination, and the other of said pairtransmitting light to said lens.